Cobra Killer: Fred Garvin’s LS1 Grand Sport Corvette Replica

Fred Garvin loves Corvettes. In fact, he currently owns seven complete models spanning four generations – from a 1963 Split Window Sting Ray to a 2004 LS6 Z06. Further adding to his gearhead street cred, Garvin is also a machinist by trade. For almost a decade, he’s operated Garvin’s Machine Shop in Killeen, Texas, where he’s made it his business to take broken cars and find a way to make them better than new. Most of Garvin’s personal Corvette collection grew from his “build it better” philosophy. In 2011, when he was looking for his next Corvette for a mixed role of track toy and cruiser, it was the highly-coveted and rare 1963 Grand Sports that drew him in.

In 1963, the lightweight GS was engineered to compete with the Shelby Cobra in Grand Touring racing; better known as the “Cobra Killer” only five were ever produced. As these ultra-rare Corvettes have continued their steady growth in value over the past fifty years, custom auto manufacturers, like Mongoose Motorsports have responded in kind, by creating replicas, giving true Corvette enthusiasts the opportunity to experience this rare gem, firsthand. “I had been interested in a Grand Sport replica for years, but couldn’t find the right one,” says Garvin. “Then one of my friends went to work for Mongoose and told me to look into their cars. I researched their cars for almost a year, and finally decided they had the right car for me.”

This Mongoose Motorsports 1963 Grand Sport replica is one of seven Corvettes that Fred Garvin owns.

Fred Garvin doesn't just know Corvettes - he's also pretty handy with engines. He has been operating Garvin's Machine Shop in Killeen, TX for almost a decade.

The car you see featured here is the result of Garvin’s lifelong passion for Corvettes, and his meticulous research to find an authentic model of the original. Once he finally acquired his own Mongoose Motorsports 1963 Grand Sports replica, Garvin didn’t just park the LS-powered Corvette safely in the garage and admire it; Garvin got busy driving and racing it. His car has already made appearances at NCCC and several SCCA race events, just the way a true Grand Sport was meant to be used.

The Mongoose replicas have no shortage of functional vents and scoops, just like the originals.

Story of the 1963 Grand Sports

It’s impossible to talk about the Mongoose Motorsports 1963 Grand Sports replica without giving some background on the original Grand Sport Corvettes that paved the way. The story is simply a remarkable legend. In 1962, Chevrolet had a bit of a problem on their hands. Some cowboy with the last name of Shelby was going around stuffing Ford V-8 engines into tiny British cars, and calling them a “Cobra.” The problem was that these pesky little buggers were dominating race circuits all around the world, and earning themselves, and Ford quite a reputation.

It was none other than the “Father of the Corvette” Zora Arkus-Duntov who came up with the idea to build the Grand Sports in secret.

Sadly, Chevrolet could do nothing to compete with Shelby or Ford. They had willfully tied their own hands in 1957 by agreeing to a ban on any direct support of racing or race teams with the rest of the AMA. Naturally, this was unacceptable to the true gearheads within General Motors. So, the “Father of the Corvette”, Mr. Zora Arkus-Duntov organized and led a group of rebel GM engineers in the development of a secret car in the backrooms of GM facilities, specifically to take on the Cobras. They fittingly referred to themselves as “Project Mongoose” – the only known predator of the cobra.

The Grand Sports were aimed directly at the Shelby Cobra, and used the same focus on a high power to weight ratio.

The Project Mongoose team planned to take the race-inspired 1963 Corvette Z06, and make it even better from the ground up, creating a lightweight body to increase the power-to-weight ratio. They used aluminum wherever they could, and built the body out of a single thin layer of hand laid fiberglass. It’s rumored that the team’s Grand Sport Corvette project cars only weighed 2,000 pounds in race trim.

For power, they developed an all-aluminum 377ci engine based on the small block, and used special hemispherical cylinder heads to make a reported 550 horsepower; an astronomical number for the day. Arkus-Duntov planned to make 125 of the Grand Sport Corvettes to meet the international standard for what could be considered a “production car”, so they could compete head-to-head with Shelby’s Cobras.

Too Much of a Good Thing…

When the Grand Sports made its testing debut at Sebring in the winter of 1962, it got off to a very fast start – running lap times within just seconds of the track record. Unfortunately, their success caused so much commotion the head-honchos at GM caught wind of the rogue Mongoose project. Needless to say, they were neither impressed nor pleased at the “Cobra Killer’s” potential, and Arkus-Duntov was ordered to immediately stop building the Grand Sports.

The Grand Sports often found themselves competing in prototype classes since there were never enough of them built to be considered a regular production car. They still proved to be very successful, and beat up on the Cobras any time they were on the track at the same time. Photo: AutoBlog

Akrus-Duntov and his team reluctantly complied and stopped building the cars, but that didn’t stop them from lending the few Grand Sports they had already built to a few private race teams. The private teams usually ran them with 427 big blocks, and had huge success. Of course, this resulted in even more backlash from GM’s critics for their perceived racing involvement. The GM brass was furious by this point, and ordered the five Grand Sports be destroyed. The Mongoose team reacted quickly, and secretly moved the three coupes into the safer hands of individuals, and hid the two roadsters at GM facilities for three years, before finally selling them to Penske Racing in 1966.

Now, 50 years have elapsed since the epic tale of the Mongoose project and the elusive Grand Sports unfolded; Amazingly, all five cars produced have survived to this day, and are among the rarest, most coveted and expensive Corvettes in history.

The Mongoose Grand Sports maintain a vintage feel that honors the originals, but still make use of more modern technology where it counts.

Enter Mongoose Motorsports

That’s where the elite team of engineers, builders and drivers at Mongoose Motorsports come in. Mongoose Motorsports, headquartered in Ravenna, Ohio, produces accurate replicas of the 1963 Grand Sport and the 1984-1988 GTP that pay tribute to the original hot-rods, with a few modern twists. While the Mongoose Grand Sports aren’t exactly cheap, they provide serious Corvette enthusiasts, like Fred Garvin, with the opportunity to own and enjoy a piece of the Grand Sport story, without spending millions of dollars.

“The last time one of the original cars went to auction, it was bid up to $5.2 million, and didn’t meet its reserve of $7 million.” said Gary Krause, Owner and Operator of Mongoose Motorsports. “It’s unbelievable. So, we offer a complete turn-key replica for $100,000, expanding the customer base while saving them quite a few bucks.”

Tech Bits on the Mongoose Grand Sport Replicas

Mongoose Motorsports has taken great care to make their Grand Sports replicas accurate and true to the original design. The flared and vented fiberglass bodies ride on a full tube frame, with the sleek body recreated from the original Grand Sports build. However, for better handling, Mongoose added attachment points for more modern C4 Corvette fully-independent suspension in both the front and rear. Instead of using a transverse leaf spring like the C4, they use a Bilstein coilover shock setup with QA1 springs for better adjustability. Garvin’s Mongoose chassis is finished off with an upgraded C4 spec Dana 44 rear end.

With almost 500 horsepower, the power to weight ratio is just unbelievable.

For stopping power, Garvin’s Mongoose utilizes stock C4 PBR twin-piston calipers and 13-inch rotors in front, with single piston calipers and 12-inch rotors in the rear. The Grand Sport is finished off with a set of PS Engineering wheels designed to closely mimic the original Grand Sport wheels, but in modern sizes to fit over the larger brakes. They measure 17 x9.5 in the front, and 17 x 11 in the rear, with 275/40/17 and 315/30/17 tires, respectively.

Garvin's Mongoose was originally equipped with the Dana 36 rear, but was recently upgraded to the beefier Dana 44 unit.

In the power department, Garvin’s Grand Sport has the distinction of being one of the very first cars Mongoose built with an LS series engine. It came with a stock 350 horsepower LS1 crate engine from Chevrolet Performance, mated to a T56 6-speed. However, being both a gearhead and a machinist, Garvin added a few performance touches of his own to the engine. He recently added a set of CNC-ported LS6 cylinder heads from Patriot Performance, and a custom ground 216/220 duration, .525/.532 lift, 110 LSA COMP cam for a nice bump in power output.

The stock LS1 was upgraded with a set of CNC LS6 heads from Patriot Performance and a custom cam from COMP.

Garvin estimates his Mongoose LS1 is now making around 450 horsepower at the crank. It’s not exactly an earth shattering number by today’s standards, but when you consider how little the Mongoose weighs, things start to come into perspective. Garvin said, “This specific car weighs 2,601 pounds. With almost 500 horsepower, the power to weight ratio is just unbelievable.” I can personally vouch for that statement, as Garvin took me for a spin in his Mongoose. First hand, I can attest it is an absolute rocket ship on wheels. It’s not just quick in a straight line either. This car can handle and stop just as well as it accelerates. Forget comparing the old-school Cobra against the modern Mongoose Grand Sport replica; the newest Shelby GT500s might be a more fitting challenge.

Mongoose went mainstream in 2011 thanks to their involvement with the Universal Pictures film “Fast Five”. Photo: Mongoose Motorsports

Mongoose Motorsports has been around for a while, but the company gained quite a bit of notoriety in 2011, thanks to their involvement with a feature film. You may have heard, or even seen, the latest installment in the Fast and the Furious saga, Fast Five, featuring a small fleet of Mongoose Grand Sports. “Someone contacted us out of the blue one day, and asked for the price on one roadster, and how many they could have,” says Krause. “I told them basically they could have as many as they could write a check for, not knowing who they were or what they wanted the cars for. The caller then told me he was from Universal Studios, and he needed five in just eight weeks for the movie.”

Normally, it takes four to six weeks to build just one Mongoose Grand Sport. Elated by the opportunity to showcase their collectibles, Krause and his team accepted the monumental undertaking of supplying the Fast Five movie production crew with all the cars they would need to film the famous train robbery scene.

“They called me back and told me the special effects department had seen pictures of our car, and they wanted two bodies, just to put on dune buggy chassis,” Krause explained. “They ended up ordering two more, and welded a 12 foot long, 14-inch diameter steel tube up the center of each for the air cannons, in order to shoot them off the train and launch them off the cliff. “ The movie production crew ordered a total of nine Mongoose Grand Sports before it was over. Krause concluded, “People see the movie and think they’ve seen just one car. They don’t realize that it took nine cars just to film that five minute scene.”

Several of the Mongoose Grand Sports saw some serious hang time thanks to the special effects department's air cannons.

Final Gear…

The Grand Sports were built by true hot-rodders for one purpose – to beat the Cobras – and they fulfilled that purpose well. Whether you see them perform death-defying feats in a feature film, or envision what it must have been like to be one of the builders of those first five secret race cars in the backrooms, the legacy of the Grand Sports has an undeniable way of capturing the imagination. They were cars that were never supposed to exist, but against all odds, they did and still survive to this day. Now, the replicas like Garvin’s Mongoose serve as a superb tribute to five of the rarest and most legendary Corvettes, while still making the most of modern technology.